Chain Tension Issue

tony.mon · Post by **tony.mon** » Sun Sep 18, 2011 7:20 pm

All I have left to suggest is to check that you haven't put a 520 chain on 530 sprockets...
If it's tighter spot on the rear sprocket you could try taking it off after taking it out for a ride (as you have already), cleaning it up thoroughly and visually inspecting it. And pressure points should show as shiny spots.

tattoo · Post by **tattoo** » Sun Sep 18, 2011 7:40 pm

i was thinking of stripping it and re-assembling it again just to make sure i hadn't missed something...i'm sure i haven't though...sounds daft but it has the fireblade wheel fitted,are they a straight wheel,carrier swap or are they interchangable...vtr carrier into blade wheel ??

lloydie · Post by **lloydie** » Sun Sep 18, 2011 9:14 pm

The carriers are the same

Can't ride but it don't stop me trying

vtryorks · Post by **vtryorks** » Sun Sep 18, 2011 11:21 pm

My plan of action is now this:

Measure the sprockets for equal dimensions and check condition for evidence of misalignment.

Check to make sure the front drive shaft is not bent, I doubt this though as I think you'd notice if it was.

Replace soft link on chain but before "mushrooming" the pins, check for a tight spot.

After that, I'm at a loss completely and I might have to get it looked at. I've had a recommendation for a local mechanic who does race bikes, so perhaps thats my final option.

Its just very annoying. I cant thank everyone enough for their time on this.

PS. Its definitely a 530 chain, DID VX model.

tinysmall · Post by **tinysmall** » Mon Sep 19, 2011 1:52 am

tattoo wrote:it's a brand new chain and sprocket set benny,the bearings feel good,no movement or noise... i'd swear the sprocket was oval but i sat and watched it through a full rotation and it looked good..

i can only discribe it as...if you set the tooth number stamp(45T) at 12noon as referance point then turn it 1 full rotation the tight spot is 12 noon every rotation of the sprocket,every 45 teeth..any ideas?

Sounds like an oval sprocket to me, and if it's only causing a few mil difference in the chain, the difference on the sprocket probably wouldn't be enough to be visible. If you still have your old rear sprocket, stick it back on the bike to see if the tight spot persists. If it doesn't you know the sprocket is shagged.

Sent from my brain using my hands with that Tapatalk thingemybob.

vtryorks · Post by **vtryorks** » Mon Sep 19, 2011 2:48 am

Ziggy suggested that earlier too, I'll add it to my list. This is so annoying though, if it turns out to be ovalised, I'll be annoyed particularly as delivery was like 4 days late. I specifically went for steel instead of aluminium from Renthal for longevity, beginning to regret it now but I guess every barrel can have a bad apple.

How common is it to find faulty new sprockets from a known brand? I cant imagine this happens very often which to be honest is why I spent so much time looking for other causes on an 8 year old bike

I dont know what I'd do without this forum to be honest, not learn very much, or ride very far, I guess

To be honest though, was saying to Tattoo, I really feel like just doing this has given me a ton of confidence over when I first obtained the bike. A lot of the things suggested here I had already tested and thought of, so I guess thats a good thing when you're doubting your mechanical brain. First time I've ever worked on a vehicle at all, so gotta start learning sometime, even if I'm a "late bloomer".

AMCQ46 · Post by **AMCQ46** » Mon Sep 19, 2011 9:30 am

+1 on oval sprocket, the steel ones are usualy fairly crude parts compared to teh renthal aluminium, so it is possible that the inner hole is over size or eccentric.

only doubt I have is that one of your mails said the you could see the WHEEL run out. if the whole wheel is running out, then it is not the sprocket

tattoo · Post by **tattoo** » Mon Sep 19, 2011 9:35 am

"late bloomer"....my brother in-law still pays to have his oil changed and he's had bikes/cars for 25yrs+ ,the last oil change bill for his street triple was Â£175

,aleast your getting your hands dirty m8

give me a bell and i'll come give you a hand.....4 hands are better than 2

Post by **sirch345** » Mon Sep 19, 2011 10:47 am

tattoo wrote:it's a brand new chain and sprocket set benny,the bearings feel good,no movement or noise... i'd swear the sprocket was oval but i sat and watched it through a full rotation and it looked good..

i can only discribe it as...if you set the tooth number stamp(45T) at 12noon as referance point then turn it 1 full rotation the tight spot is 12 noon every rotation of the sprocket,every 45 teeth..any ideas?

vtryorks, This may sound as if I'm a fussy sod (well I am

) but when I fit a new rear sprocket sometimes I have noticed a little bit of play between the fixing bolts and the holes in the sprocket. What I try to do is centralise the sprocket on the bolts while the wheel is lying flat, then tighten the carrier nuts as tight as I can (in a criss-cross motion) with the tee bar and socket. I then re-fit the wheel and finish tightening the nuts with the torque wrench.

Chris.

vtryorks · Post by **vtryorks** » Mon Sep 19, 2011 1:19 pm

Cheers fellas,

Have to say the rear sprocket was a very tight fit. Had to use a rubber mallet to gently tap it on but against its something to double check. Either way, the rear sprocket will have to come off so I'll take extra care when refitting the old one to test.

Tattoo, offer appreciated, thank you

vtryorks · Post by **vtryorks** » Mon Sep 19, 2011 7:40 pm

Alright,

I naively thought measuring the sprocket dimensions would be easy, but it clearly is not.

I swapped out my sprocket for the old one, tight spot is gone. However, wear in the sprocket could contribute, so I made the chain much tighter than it should be whilst on the stand to hopefully compensate for any sprocket wear. Still no tight spot.

Sounds like the damn sprocket but I cant prove it. Main issue is trying to find the exact diameter.

After thinking about it, even 0.5mm distortion at the widest point would be made up of increments of distortion from 180 degree's of the circle, added up, these would contribute significantly to chain tension. So I suspect, without specialist equipment, its impossible to prove.

I'm going to ask DK for a replacement tomorrow anyway, if that also has the problem (bad batch) I'm going to order a Renthal and see if I have more joy with that.

Just a couple of questions if I may:

Is there any way that my old sprocket wear could mask the tight spot (with new chain and front sprocket still fitted)?

Is there any problem with running a steel front sprocket and an aluminium rear?

Cheers,

Martin

AMCQ46 · Post by **AMCQ46** » Mon Sep 19, 2011 7:43 pm

sounds like there is a sprocket problem

it is ok to have steel front and aly rear..........all front sprockes are steel, as the loading is inversly proportional to the number of teeth. aly wouldnt survive on the front

and I very much doubt the old sprocket had worn to mask the problem.........if anything it would have got worse, but also what are the chances that you put it on in the original position .........not likley, so I would be 99% sure you have found the problem

tinysmall · Post by **tinysmall** » Mon Sep 19, 2011 7:45 pm

Doubt it and no, in that order.

turbo_billy · Post by **turbo_billy** » Mon Sep 19, 2011 7:48 pm

No problem running a mix of the two sprockets. What you have to remember is the rear ally sprocket is not your bacofoil type but a high grade, high strength alloy that is lighter than its steel equivalent.

I have been following this thread and believe that it is the sprocket that is at fault. You said it was tight to fit to the hub. Are there any noticeable ridges on the inner hole that could be forcing the sprocket over on the mounting holes?

In answer to your worn sprocket masking the symptoms, I don`t think this would be an issue as it would be the teeth that have worn and not the centre mass.

Hope the replacement cures your problems.

Regards

Tim :beer:

vtryorks · Post by **vtryorks** » Mon Sep 19, 2011 7:52 pm

turbo_billy wrote:You said it was tight to fit to the hub. Are there any noticeable ridges on the inner hole that could be forcing the sprocket over on the mounting holes

No ridges, it seems well made really, thats why I never suspected it over an 8 year old bike...

It is a tight fit, but Tattoo said he's used DID sprockets in the past, which were also a tight fit. Like me, he was initially surprised to find he needed a rubber mallet to tap it on.

Appreciate all the help and I hope this thread helps someone else eventually too even if my initial description of the symptoms was off.

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